Low-color ultraviolet absorbers for high UV wavelength protection applications

ABSTRACT

Novel ultraviolet absorbing compounds that are liquid in nature, are extremely low in color (and thus permit use without the concomitant necessity of adding large amounts of other coloring agents to combat such discoloring), and are highly effective in providing protection in wavelength ranges for which previous attempts at low-color ultraviolet absorbers have failed are provided herein. Such compounds provide such excellent, inexpensive, and beneficial protection from ultraviolet exposure within various media, including, but not limited to, clear thermoplastics. The particular compounds are generally polymeric in nature including various chain lengths of polyoxyalkylenes thereon and are liquid in nature to facilitate handling and introduction within the target media. In addition, such ultraviolet absorbers also exhibit extremely low migratory properties thereby providing long-term protective benefits to the target media as well. This invention also concerns the end products, specific broadly defined types of compounds providing such beneficial characteristics, methods of making such low-color compounds, and methods of producing such clear, UV protected end products.

FIELD OF THE INVENTION

[0001] This invention relates to novel ultraviolet absorbing compoundsthat are liquid in nature, are extremely low in color (and thus permituse without the concomitant necessity of adding large amounts of othercoloring agents to combat any discoloring within clear, colorlessapplications), and are highly effective in providing protection inwavelength ranges for which previous attempts at low-color ultravioletabsorbers have failed. Such compounds provide such excellent,inexpensive, and beneficial protection from ultraviolet exposure withinvarious media, including, but not limited to, clear thermoplastics. Theparticular compounds are generally polymeric in nature including variouschain lengths of polyoxyalkylenes thereon and are liquid in nature tofacilitate handling and introduction within the target media. Inaddition, such ultraviolet absorbers also exhibit extremely lowmigratory properties thereby providing long-term protective benefits tothe target media as well. This invention also concerns the end products,specific broadly defined types of compounds providing such beneficialcharacteristics, methods of making such low-color compounds, and methodsof producing such clear, UV protected end products.

BACKGROUND OF THE PRIOR ART

[0002] All of the U.S. patents cited throughout this specification arehereby entirely incorporated herein.

[0003] Ultraviolet absorber compounds have been utilized for a number ofprotective applications, including within compositions for coveringskin, on and within apparel and other types of textiles, withintransparent plastic containers, and the like, to combat the harmful anddegradable effects of certain wavelengths of light in the UV spectrum.The best known UV absorbers are benzotriazoles, available from Cibaunder the tradename Tinuvin®, and benzophenones, available from CytecIndustries under the trademark Cyasorb™. Such compounds are highlyeffective in their UV absorber capacity; however, they are quite costly,can prove difficult to incorporate within different target media, andtend to migrate from within certain types of media (such as plastics).Furthermore, these two well known types of UV absorbers present handlingdifficulties in that they are generally produced and utilized in powderform and have relatively low melting points. Particularly, withinplastic media, the powder form of these compounds is problematic; aliquid is much easier to handle, does not require melting, and providesmore effective and thorough mixing throughout the target plastic.Additionally, these previously utilized UV absorbers provide UVprotection over a relatively narrow range of wavelengths (λ_(max) fromabout 290 to about 340 nm for benzotriazoles; from 260 to 300 nm forbenzophenones), which ultimately leaves a potentially damaging range ofunprotected UV exposure (to about 400 nm). Attempts to increase theamount of such UV absorber compounds in order to provide potentialprotection over such a broader wavelength range is ineffective, not tomention such greater amounts of UV absorbers increases the production ofunwanted colorations within target clear plastics and other likeapplications such that masking compounds (e.g., bluing agents, forexample) must be utilized in relatively high amounts to combat thediscoloring effect. Thus, there exists a need to provide a highlyeffective, liquid ultraviolet absorber which exhibits a versatility tobe incorporated within or applied to different and various media andsubstrates and which, alternatively, can provide protection over therange of wavelengths in the UV spectrum of from about 290 to about 400nm (in order to provide the best overall protection from possible harmand/or degradation associated with UV exposure).

[0004] Methine-based compounds, in particular certain malonatederivatives, as in European Patent Abstract 350-386-A, to L'Oreal SA,are useful as UV absorbers in cosmetic sunscreen compositions, aregenerally inexpensive to make, and provide UV protection in the spectrumfrom about 280 to about 360 nm. However, such compounds are highlysoluble in organic solvents and would therefore easily migrate fromsolid compositions, such as plastics, upon introduction therein. Thus,although the utilization of an effective UV absorber, such as a malonatederivative, within plastics, may be highly desirable, such has neverbeen taught nor fairly suggested within the prior UV absorber art due tothe great difficulty in producing such a stable, and thus highlyeffective, UV absorbing composition from such a methine-based source.There exists a need then to produce an inexpensive UV absorber whichexhibits the requisite ability to remain within media such asthermoplastics and the like (as noted above), and thus provide necessaryand desirable protection from degradation due to UV exposure.

[0005] Further developments for the ultraviolet protection of certainpolymeric media (such as polyesters) have included methine-basedcompounds which, to be effective in terms of low extraction from such athermoplastic, must be introduced during the actual polymerizationreaction of the base thermoplastic polymer itself. For example, U.S.Pat. No. 4,617,374 to Pruett et al. teaches such UV absorbers forpolyester end-uses. Again, however, such compounds exhibit very highextraction results unless they are added as to-be-polymerized reactantsthemselves with the ester monomers during the polymerization step. Insuch an instance, these UV absorbers are actually integrated within thepolymer, and not just mixed within the thermoplastic medium. As such,although such compounds do exhibit excellent results when polymerizedwithin the target polyester, unfortunately such compounds are limited intheir versatility since the only time during which effectiveintroduction is permitted is during the aforementioned polymerizationprocedure. There thus still remains a need to provide a more versatileUV absorber for thermoplastic end-uses such that the producer canintroduce the UV absorber at any time during the production of thetarget thermoplastic such that the additive does not exhibit such highextraction and yet still provides excellent UV absorbing propertiesthereto.

[0006] It has now been found that through the addition ofpolyoxyalkylene chains onto certain ultraviolet absorber compounds,greater versatility of potential uses for the new UV absorber isprovided, particularly in terms of the needed low-extraction as notedabove. Therefore, it has been found that such polyoxyalkylenatedcompounds (such as those, without intending to limit the breadth of theinvention, the methine-based compounds utilizing vanillin and resorcinolas starting materials) provide UV absorbers which are highly effectivein filtering harmful UV-A and UV-B rays over a broad spectrum (λ_(max)from about 280 to about 400 nm, more preferably from about 320 to about400 nm). Furthermore, it has been found that in combination with abenzotriazole and/or a hydroxybenzophenone, or other similar type of UVabsorber compound, the resultant composition is accorded protection froma great amount of potentially damaging UV radiation (from approximately250 to about 400 nm). Additionally, such a combination is highly stablewithin the desired media, and thus provides long-term protection to thedesired sample stored within the target treated plastic article.Additionally, such compounds are very low in color when prepared inaccordance with certain procedures, most notably with certainalkoxylation catalysts, including, without limitation, metal hydroxidesand other bases, both alone and in the presence of amine-basedalkoxylation catalysts (particularly with affinities for availableprotons), as well as rare earth phosphate salts, such as those taughtwithin U.S. Pat. Nos. 5,057,627, 5,057,628, 5,059,719, 5,118,870,5,208,199. Such low-color alternatives thus provide the basis foreffective utilization within colorless (clear and transparent)applications, such as the desired clear plastics, while simultaneouslyproviding the necessary effective UV protection.

[0007] Although some interest has been demonstrated within the area ofcertain methine-based UV absorber compounds (i.e., L'Oreal's malonatederivatives), to date there has been no disclosure or fair suggestionregarding the utilization of the polyoxyalkylenated derivatives of suchUV absorbers in that capacity within certain media (such as, forexample, plastics), or on other surfaces (skin, textiles, for example),or in other applications (inks, and the like, for example). Inparticular, no disclosures exist concerning low-color, low-extraction(migration) polyoxyalkylenated UV absorber compounds that provideeffective protection from UV exposure between the wavelengths of fromabout 320 to about 400 nm. There is thus a great need within the UVabsorber market, and most particularly within the transparent plasticfilm and container markets (for storing and protecting food, pills, andthe like) for such types of improvements associated with relativelyinexpensive materials and processes provided by the inventivepolyoxyalkylenated methine-based UV absorber compounds. Otherultraviolet absorbing compounds and compositions have been developed ormodified for certain plastic (thermoplastic, thermoset, etc.)applications, such as a class of compounds known by the name ofTinuvin®, available from Ciba, and noted above. Although such compoundsappear to provide very good ultraviolet protection both to the plasticitself and to any stored liquids, solids, etc., within a container madetherewith such plastics, unfortunately such a class of compoundsexhibits undesirable or problematic deficiencies. In particular, thebreadth of protection within the UV spectrum is generally limited tofrom about 320 to about 375 nm with such compounds. Thus, they generallydo not provide adequate UV protection to contents of plastic packagingover the entire range of UV wavelengths. Also, such Ciba compounds aregenerally naturally solid in nature and thus are either dispensed withintarget resins as solid powders or must be dispersed within liquids bythe end-user at time very close to dispensing in order to be effective.If any such Ciba UV absorbers are in fact liquid, they still are limitedin their breadth of UV protection in terms of wavelength ranges. Lastly,such Ciba compounds exhibit relatively high extraction levels andmigratory characteristics from within target plastic resins,particularly thermoplastics such as polyethylene terephthalates. Thus,although such compounds are effective for UV protection to a certainextent, there are a number of drawbacks for which improvements arehighly desired and necessary. To date, there thus remains a great needto provide an effective UV absorber that eliminates the above-noteddeficiencies.

OBJECTS OF THE INVENTION

[0008] It is therefore an object of this invention to provide novellow-color, low-thermoplastic-migrating (e.g., low-extraction),ultraviolet absorbing compounds, which may further be liquid whenpresent in their pure, undiluted states at room temperature and thatprovide UV protection over a broad range of wavelengths up to at least390 nm. A further objective of this invention is to provide a polymericUV absorber that can be used within various media and on differentsubstrates as an effective UV filtering compound or within a suitablecomposition for protection against potentially harmful ultraviolet rays.A further object of this invention is to provide a methine-based UVabsorber that provides bright and clear plastic articles. It is yetanother object of this invention to provide certain polyoxyalkylenatedmethine-based ultraviolet absorbers which do not require the presence ofan appreciable amount of bluing agent in order to provide alow-yellowing effect within clear thermoplastic applications (and thusprovides brighter clarity within the target plastic or other medium).Yet another object of the invention is to provide an effective UVabsorbing composition or article which comprises the inventivelow-color, low-thermoplastic-migrating ultraviolet absorbing compounds,particularly with wherein such compounds liquid in nature when undilutedat room temperature. Additionally, an object of this invention is toprovide a low-color UV absorber that provides protection to contentswithin clear thermoplastic packages such that degradation will notreadily occur due to exposure to UV wavelengths within the range of 250to 400 nm. Also, methods of producing such low-color UV absorbingcompounds are also provided.

DESCRIPTION OF THE INVENTION

[0009] Accordingly, the present invention thus encompasses a clearthermoplastic article having an average thickness of at most 35 milscomprising at least one ultraviolet absorber compound exhibitingultraviolet absorption characteristics over the range of wavelengthsfrom about 300 to about 400 nm such that said article exhibits a UVtransmission of at most 10% at the 390 nm wavelength; and wherein saidat least one compound exhibits an extraction level from saidthermoplastic article measured as the level of absorbance exhibited by aheated alcohol extract solution after 2 hours exposure of at most 0.1absorbance units in a cell with a 10.0 cm optical path length,preferably 0.05, more preferably 0.025, and most preferably as low as0.0; wherein said ultraviolet absorber comprises at least onepoly(oxyalkylene) chain of at least six total moles of oxyalkylene, oralternatively wherein said ultraviolet absorber is introduced withinsaid thermoplastic at any time during the production of said article, oralso alternatively, wherein said at least one ultraviolet absorber is aliquid prior to incorporation within said thermoplastic article and atroom temperature in its pure, undiluted state. Also considered part ofthis invention is the same clear thermoplastic article as above whereinsaid thermoplastic article simultaneously exhibits a yellowness level ofat most 2.5 and a brightness level of at least 90. Additionallyencompassed within this invention is a liquid ultraviolet absorbercompound exhibiting a Gardner color value of at most 11, wherein saidultraviolet absorber exhibits an extraction level from polyethyleneterephthalate measured as the level of absorbance exhibited by a heatedalcohol extract solution after 2 hours exposure of at most 0.1absorbance units, preferably 0.05, more preferably 0.025, and mostpreferably as low as 0.0. Further encompassed within this invention isan ultraviolet compound conforming to the structure represented byFormula (I)

[0010] wherein R₁, R₂, R₃, R₄, and R₅ are the same or different and areselected from the group consisting of C₁₋₂₀ alkyl, halo, hydroxyl,hydrogen, cyano, sulfonyl, sulfo, sulfato, aryl, nitro, carboxyl, C₁₋₂₀alkoxy, and B-A, wherein at least one of R₁, R₂, R₃, R₄, and R₅ is B-A,wherein B is selected from the group consisting of N, O, S, SO₂, SO₃,CO₂, and A is represented by the Formula (II)

[polyoxyalkylene constituent]_(z)R′  (II)

[0011] wherein polyoxyalkylene constituent is selected from the groupconsisting of at least three monomers of at least one C₂₋₂₀ alkyleneoxygroup, glydicol, glycidyl, or mixtures thereof, R′ is selected from thegroup consisting of hydrogen, C₁₋₂₀ alkoxy, C₁₋₂₀ alkyl, and C₁₋₂₀esters; wherein if B is N, then Z is 2, and if B is other than N, then Zis 1; X and Y are the same or different and are selected from the groupconsisting of hydrogen, cyano, C(O)OR, C(O)R, C(O)NR″R′″, C₁₋₂₀alkyl,and C₁₋₂₀ alkoxy, or X and Y are combined to form a ring system, and R,R″, and R′″ are defined as above for any of R₁, R₂, R₃, R₄, and R₅; andwherein if X and Y are not combined to form a ring system then at leastone of said X and Y is either cyano or hydrogen. Another important partof this invention is thus a low-color ultraviolet absorbing compound aswell as a method of forming such a low-color ultraviolet absorbercompound wherein said ultraviolet absorber compound conforms tostructure represented by Formula (III)

[0012] wherein A is represented by the Formula (II)

[polyoxyalkylene constituent]_(z)R′  (II)

[0013] wherein polyoxyalkylene constituent is selected from the groupconsisting of at least three monomers of at least one C₂₋₂₀ alkyleneoxygroup, glycidol, glycidyl, and any mixtures thereof, and R′ is selectedfrom the group consisting of hydrogen, C₁₋₂₀ alkoxy, C₁₋₂₀ alkyl, andC₁₋₂₀ esters; wherein the method comprises the sequential steps of

[0014] a) reacting vanillin with at least one compound selected from thegroup consisting of at least one compound comprising at least oneoxyalkylene-containing group selected from the group consisting of atleast one C₂-C₂₀ alkylene oxide, glycidol, and any mixtures thereof, inthe presence of a catalyst; and

[0015] b) reacting the reaction product of step “a” with at least onealkyl cyanoester (such as, without limitation ethyl cyanoacetate). Sucha novel compound should exhibit a Gardner color level of at most 10 whenpresent within a methanol solution at a 5% concentration by volume and amaximum ultraviolet absorption within the range of wavelengths of 320and 400 nm, with a measured ultraviolet transmission of at most 10% ateach wavelength under 400 nm, preferably under 390 nm, when incorporatedat a loading of at most 0.5% by weight within a polyester article havinga thickness of at most 1 mm. Also, such a novel compound may also beliquid in its pure, undiluted state at room temperature, again tofacilitate handling and introduction within desired media, such as,without limitation, thermoplastics.

[0016] Also, this invention encompasses a method of forming a low-colorultraviolet absorber compound wherein said ultraviolet absorber compoundconforms to structure represented by Formula (IV)

[0017] wherein A is represented by the Formula (II)

[polyoxyalkylene constituent]_(z)R′  (II)

[0018] wherein polyoxyalkylene constituent is selected from the groupconsisting of at least three monomers of at least one C₂₋₂₀ alkyleneoxygroup, glycidol, glycidyl, and any mixtures thereof, and R′ is selectedfrom the group consisting of hydrogen, C₁₋₂₀ alkoxy, C₁₋₂₀ alkyl, andC₁₋₂₀ esters; said method comprising the sequential steps of

[0019] a) reacting resorcinol with a compound selected from the groupconsisting of at least one compound comprising at least oneoxyalkylene-containing group selected from the group consisting of atleast one C₂-C₂₀ alkylene oxide, glycidol, and any mixtures thereof, inthe presence of a catalyst to produce a polyalkoxylated resorcinol; and

[0020] b) reacting the reaction product of step “a” with a compoundwhereby said compound protects the polyalkoxylate hydroxyl groups;

[0021] c) converting the product of step “b” to an aromatic aldehydethrough the production of a Vilsmeier complex;

[0022] d) subsequently reacting the aldehyde of step “c” with a basicsubstance which will liberate the polyalkoxylate hydroxyl groups; and

[0023] e) subsequently reacting the resultant product of step “d’ withan alkyl cyanoester (such as, without limitation, ethyl cyanoacetate).

[0024] Such a novel compound, as that defined by structure (III), above,should exhibit a Gardner color level of at most about 11 when presentwithin a methanol solution at a 5% concentration by volume and a maximumultraviolet absorption within the range of wavelengths of 320 and 400nm, with a measured ultraviolet transmission of at most 10% at eachwavelength under 400 nm, preferably under 390 nm, when incorporated at aloading of at most 0.5% by weight within a polyester article having athickness of at most 1 mm. Also, such a novel compound may also beliquid in its pure, undiluted state at room temperature, again tofacilitate handling and introduction within desired media, such as,without limitation, thermoplastics.

[0025] Compositions comprising such compounds of (III) and (IV) are alsoencompassed within this invention, particularly those comprising suchcompounds and bluing agents, as liquids or as pellets for furtherintroduction within desired molten thermoplastic formulations. Methodsof making such compositions, particularly thermoplastics, comprisingsuch compounds of (I), (III), and (IV) are also contemplated within thisinvention.

[0026] The term “thermoplastic” is intended to encompass any syntheticpolymeric material that exhibits a modification in physical state fromsolid to liquid upon exposure to sufficiently high temperatures. Mostnotable of the preferred thermoplastic types of materials arepolyolefins (i.e., polypropylene, polyethylene, and the like), polyester(i.e., polyethylene terephthalate, and the like), polyamides (i.e.,nylon-1,1, nylon-1,2, nylon-6 or nylon-6,6), polystyrenes,polyurethanes, polycarbonates, polyvinyl halides (i.e., polyvinylchloride and polyvinvyl difluoride, as merely examples), and the like.Preferred thermoplastics within this invention are polyesters, and mostpreferred is polyethylene terephthalate.

[0027] Such thermoplastic articles include bottles, storage containers,sheets, films, fibers, plaques, hoses, tubes, syringes, and the like.Included within this list would be polyester, polystyrene and other likeclear resinous materials in sheet form which are present within windowsfor strength and resiliency functions. In such an instance, thelow-color UV absorbers of this invention would provide or contribute toexcellent UV protection for contents with target packaging articles(such as bottles, containers, and the like) or persons located indoors(such as within houses, buildings, cars, and the like, comprisingwindows with such additives included therein). Basically, the possibleuses for such a low-color, low-migratory UV absorber is voluminous andcannot easily be enveloped. Other possible end-uses, however, wouldinclude solvent systems, printing inks, textile treatment compositions(either on or within textiles, fibers, fabrics, and the like).

[0028] Other types of articles contemplated within this invention forthe particularly disclosed clear UV protected thermoplastics include,again without limitation, films, sheets, bottles, containers, vials, andthe like. Ultraviolet absorbers are typically added to such compositionsduring the injection molding (or other type of molding, such as blowmolding), thereof, including, and without limitation, by mixing theliquid absorber with resin pellets and melting the entire coatedpellets, or through a masterbatch melting step while the resin andabsorber are pre-mixed and incorporated together in pellet form. Suchplastics include, again without limitation, polyolefins, polyesters,polyamides, polyurethanes, polycarbonates, and other well known resins,such as those disclosed within U.S. Pat. Nos. 4,640,690, to Baumgartneret al., and 4,507,407, to Kluger et al. under the term “thermoplastics”.Generally, such plastics, including the UV absorber additive, are formedthrough any number of various extrusion, etc., techniques, such as thosedisclosed in the aforementioned U.S. patents. Preferred thermoplasticsare polyesters, such as, in one non-limiting embodiment, polyethyleneterephthalate. “Plastic packaging” thus encompasses containers, sheets,blister packages, and the like, utilized for storage purposes and whichinclude the plastics in any combination as noted above.

[0029] The term “pure, undiluted state” as used in conjunction with theUV absorbing compounds indicates that the compounds themselves withoutany additives are liquid at room temperature. Thus, there is no need toadd solvents, viscosity modifiers, and other like additives to the UVabsorbers to effectuate such a desirable physical state.

[0030] Such inventive polymeric UV absorbers, as noted above, are verylow in color [e.g., do not exhibit a b* value (indicating a degree ofyellowing in this instance) above 2.5 on the CieLab scale]. Thus, thereis no need to add appreciable amounts of other colorants (such as bluingagents, for example), acid scavengers, and other like additives, to theparticular UV absorber to provide such desired low-color (low-yellowing)characteristics. It should be well understood by one of ordinary skillin this art that such a benefit as low-yellowing without any otheradditives present applies solely to the particular compounds and doesnot indicate that any compositions comprising such compounds solelyinclude such inventive compounds as thermoplastic additives. In fact,other additives, such as the aforementioned bluing agents, acidscavengers, antistatic agents, optical brighteners, and the like, mayalso be added to these compounds prior to, during, and/or afterintroduction within the desired end product medium (such asthermoplastic, for example). The polymeric species may be determinedthrough destructive analysis (methanolysis, for example), and furtherspectrophotometric analysis thereof to locate any signatures of ananiline poly(oxyalkylene) comopund, as one example.

[0031] The term “solvent systems” encompasses any aqueous or organicliquid formulations. Non-limiting examples of the intended aqueoussystems include cleaning solutions, detergents, fabric softeners,marking inks and colorants, and keratin dyes. Non-limiting examples oforganic formulations include the non-aqueous types of cleaningsolutions, detergents, fabric softeners, marking inks and colorants,keratin dyes, as well as descalers, surfactant formulations, hydrocarboncompositions, and the like. The addition of inventive UV absorbers isaccomplished through the mere addition of the liquid compound within thetarget solvent system with simultaneous and thorough mixing.

[0032] Printing inks include compositions utilized as colorants within,again, as merely examples, pens, including, but not limited toball-point and fountain pens, dot-matrix printers, toners for standardcopy machines, ink-jet applications, permanent markers, dry-erasemarkers, newsprint, magazine print, laser jet printers, and the like.The addition of inventive UV absorbers is accomplished through the mereaddition of the liquid compound within the target printing inkformulations with simultaneous and thorough mixing.

[0033] The term textile treatment compositions comprises both anyformulations for application on textiles (and thus leaving at least atemporary UV absorbing coating, or the like, on the textile surface).Incorporation of the inventive compounds within fibers of textiles isalso encompassed within this term and thus within this invention. Skinprotectant and skin tanning formulations basically encompass anycompositions comprising the novel UV absorbing compound which isutilized to protect skin from solar radiation.

[0034] The benefits accorded by the aforementioned novel ultravioletabsorbing compounds are plentiful, considering the state of the art atthis time. For example, clear thermoplastic or thermoset article arehighly desirable in order to facilitate recognition of compositions andformulations contained within such articles, for evident reasons. Foraesthetic purposes, such clear articles should not exhibit anydiscoloration. With most standard UV absorbers used today, yellowing isprevalent due to the inherent nature of the compounds themselvesproviding such color in order to absorb within the UV range. Thus, asnoted previously, bluing agents, in relatively high amounts, arerequired to counter this effect and provide the desired uncolored resin.The inventive plastics (and inventive compounds) do not exhibit suchdiscolorations to such a degree and thus, even though some yellowing maybe exhibited by such compounds, and thus within the targetthermoplastics, the use of much lower amounts of bluing agents providesthe needed clear, uncolored resin, thereby saving on cost and reducingthe work needed to provide such a proper clear article as well as abrighter article. Because bluing agents not only aid in preventingyellowness within target media, but also contribute grayness therein aswell, the utilization of large amounts of such agents is generallyavoided. The inventive compounds thus provide clarity with low graynesslevels due to the low-color aspects available therewith. As a result,the desired clear plastics exhibit heretofore unattained brightnesslevels with simultaneously extensive and effective ultravioletprotection over a wide range of wavelengths (as discussed above).Furthermore, such effective UV absorbing characteristics are noticeablein terms of protection for certain contents of target thermoplasticstorage articles. As discussed further below, such inventive UVabsorbers exhibit highly desirable ultraviolet absorptioncharacteristics over the range of wavelengths from about 300 to about400 nm such that an aqueous composition of riboflavin present withinsaid clear thermoplastic article will exhibit a degradation rate of atmost 75% after ultraviolet exposure over the wavelength range of 300 to400 nm after 20 hours of exposure to high intensity UV light (e.g., andfor all such experiments listed hereinafter, under at least 8 totalSylvania® 350 Blacklight bulbs, Model Number F40/350 BL, 40 watts each).

[0035] Furthermore, such inventive compounds exhibit extremely lowmigratory (e.g., low-extraction) levels from plastics and other media.The presence of poly(oxyalkylene) chains thereon provides a veryversatile UV absorbing compound as a liquid or low viscosity additivethat, exhibits thorough and effective mixing when introduced within thetarget thermoplastic and following molding and cooling also exhibitsvery low extraction levels therefrom. Such resultant low extractionlevels are exhibited by said inventive compound (as well as saidinventive thermoplastic) no matter when the inventive UV absorbercompound is introduced within the target thermoplastic during productionthereof. Thus, introduction at the polymerization stage (as in Pruett etal.), as well as at the injection molding stage, or even during theinitial mixing stage of the target thermoplastic with its additives, allaccord a very low-extraction result for the inventive UV absorbers. Suchversatility thus permits the user to set up his reaction method in termsof other limitations, rather than on the limits imposed by the effectiveintroduction of a low-extraction UV absorber compound (as now is thecase in Pruett et al.). Such a benefit thus accords the user theflexibility to introduce the necessary effective UV absorber at any timeduring thermoplastic production. Hence, introduction of such polymericcompounds within the target resins at any time during the productionmethod is facilitated by the liquid nature of most of the inventivepolymeric UV absorber compounds. Handling is greatly improved thereby,and more thorough dispersion within the desired medium is accomplishedas well. Again, costs are reduced due to simplicity and reliability isincreased with more thorough mixing, etc., through utilization of suchinventive compounds with simultaneous or concomitant reliability interms of performance and low extraction characteristics.

[0036] Additionally, such a highly reliable, easy-to-handle, low-color,and low-migratory (low-extraction) UV absorbing compound also provides agreater range of protection than the standard UV absorbers now providedwithin the industry. Generally, such standard UV absorbers are effectiveup to about 380 nm, even with an increase in amount of such a compoundwithin the target medium (polyester, for example). Even with increasedamounts of such standard UV absorbers present within the target media(such as thermoplastics), the discolorations within the target mediumare more pronounced without a correlated benefit in a greater range ofprotected wavelengths. To the contrary, the inventive compounds provideprotection up to about 400 nm. This effect is easily shown through theselection of a certain chemical compound prevalent within stored liquidsand solids that is highly susceptible to UV attack and decomposition.For instance, as is shown in greater detail below, riboflavin (VitaminB₂) meets such a description; in comparison with standard UV absorbers(Tinuvin® 234, for example), the protection accorded riboflavin withinan aqueous solution and stored within a clear polyethylene terephthalatecontainer and exposed to a UV source between 320 and 400 nm for 20 hoursis significantly higher for the inventive vanillin- and resorcinol-basedcompounds. Such an improvement, in combination with any or all of theother characteristics exhibited by these inventive compounds, thus showsthe novelty and usefulness of such compounds, particularly within clear,and possibly plastic, applications.

[0037] In particular, such inventive UV absorbing compounds then conformto the following structure (I)

[0038] wherein R₁, R₂, R₃, R₄, and R₅ are the same or different and areselected from the group consisting of C₁₋₂₀ alkyl, halo, hydroxyl,hydrogen, cyano, sulfonyl, sulfo, sulfato, aryl, nitro, carboxyl, C₁₋₂₀alkoxy, and B-A, wherein B is selected from the group consisting of N,O, S, SO₂, SO₃, and A is represented by A is represented by the Formula(II)

[Alkyleneoxy constituent]_(z)R′  (II)

[0039] wherein Alkyleneoxy constituent is selected from the groupconsisting of C₂₋₂₀ alkyleneoxy, R′ is selected from the groupconsisting of hydrogen, C₁₋₂₀ alkoxy, C₁₋₂₀ alkyl, and C₁₋₂₀ esters;wherein if B is N, then Z is 2, and if B is other than N, then Z is 1; Xand Y are the same or different and are selected from the groupconsisting of hydrogen, cyano, C(O)OR, C(O)R, C₁₋₂₀alkyl, and C₁₋₂₀alkoxy, and R is defined as above for any of R₁, R₂, R₃, R₄, and R₅;wherein at least one of R₁, R₂, R₃, R₄, and R₅ is B-A; and at least oneof said X and Y is either cyano or hydrogen. Preferably, when X is anester group, Y is cyano, B is O, Preferably, Alkylene constituent iseither oxyethylene, oxypropylene, or oxybutylene, with oxyethylene andoxypropylene most preferred (between 2 and 100 units of such monomers;preferably between 2 and 50; and most preferably, between 5 and 20); andR′ is preferably hydrogen. Such compounds thus must also exhibit theaforementioned low-color and low-migration (from the target medium, suchas plastic) characteristics, as well as existing as a liquid when in itsundiluted state at room temperature.

[0040] Preferably, such a low-color ultraviolet absorbing compoundsconform to the structures represented by Formulae (I), (III), and (IV),above. Such compounds are poly(oxyalkylenated) in order to provide thedesired low extraction levels from thermoplastics as discussed above.The ability to provide such low-color species for structures conformingto Formulae (I) and (III), above, and thus not resorcinol-basedcompounds, is apparently controlled through the utilization of specifictypes of alkoxylation catalysts, including, without limitation, rareearth salts (such as lanthanum phosphates), particular metal hydroxides(such as potassium hydroxide both alone and in the presence of compoundshaving a strong affinity for free and/or available protons within thereaction medium itself, hereinafter referred to as “proton sponge”), andthe like. Such catalysts, particularly the rare earth phosphates,apparently are configured in such a way that the levels of impuritiesand starting materials present within the reaction itself if drasticallyreduced in comparison with other standard alkoxylation catalysts (suchas sodium hydroxide) (although the true reasons behind such beneficiallow-color production is not completely understood). Preferred arelanthanum phosphate catalysts which are white powdery materials having amean particle size (D50) of between 5 and 50 microns, a lanthanum,content of at least 58% by weight, and is substantially free from anychlorine. The poly(oxyalkylenated) products catalyzed therefrom exhibitsmuch less color in comparison with other standard alkoxylation catalysts(such as NaOH, as noted previously). Such a preferred catalyst is thesame utilized within the particular examples below.

[0041] Furthermore, without intending to be limited to any specificscientific theory, it is postulated that such aforementioned protonsponge compounds prevent the potentially deleterious reaction ofstrongly charged proton species from attacking the final reactants andreaction products and thus curtails the production of discoloringcompounds within the final product itself. Examples of such protonsponge compounds include, without limitation, 1,8-bis(dimethylamino)naphthalene, 1,8-bis(diethylamino)-2,7-dimethoxynaphthalene,4,5-bis(dimethylamino)-fluorene, 4,5-bis(dimethylamino)phenanthrene,quino[7,8-n]quinoline, and the like, with1,8-bis(dimethylamino)naphthalene preferred.

[0042] Preferably, the alkoxylated compounds include either ethyleneoxide or propylene oxide, or mixtures of both, thereon having chainlengths from 2 to about 100; more preferably such a chain length if fromabout 2 to about 50; and most preferably such a chain length is fromabout 5 to about 10, with all ethylene oxide also highly preferred. Thevanillin-based UV absorbing compounds of structure of Formula (III) arethus preferred embodiments of structure of Formula (I).

[0043] The structures conforming with Formula (IV) are also preferredembodiments of the structure of Formula (I)] are produced as low-colorpoly(oxyalkylenates) through the above-noted modified formylation of ahydroxyl-protected alkoxylated resorcinol through Vilsmeier complexationand subsequently deacetylating such a compound. In such an instance, theinitial alkoxylation may be performed through catalysis with moststandard alkoxylation catalysts. Again, the same types of oxyalkylenesand chain lengths thereof as noted above for the structures of Formulae(I) and (III) are preferred as well for the structure of Formula (IV).The starting material within the method of making such a compound isthus any resorcinol-based compound, preferably resorcinol itself. Afteralkoxylation, the resultant compound is reacted with a protectingcompound for the free hydroxyls thereon. Such a protecting compound maybe an ester anhydride, preferably at least one of C₁-C₂₀ esteranhydride, more preferably acetic anhydride. The protected compound isthen formylated with a Vilsmeier complex formed from, for example,N,N-dimethyl formamide and phosphorous oxychloride and can be anystandard compound of this type, including, without limitationdisubstituted formamides reacted with either phosphorous oxychloride,phosgene, or triflic acid, as merely examples. Of course, any otheraldehyde-forming group will function within this method in order toproduce an aromatic aldehyde based on the protected resorcinolpolyoxyalkylenated compound [such as resorcinol (6 moles of ethyleneoxide aka EO) diacetate]. In order to obtain a low color aldehydeproduct, the formylation reaction is run at a lower temperature (i.e.70° C. vs. 90° C.) and in the presence of hypophosphorous acid.Hypophosphorous acid is a well known reducing agent and it is believedthat its presence counters the formation of highly colored oxidizedspecies. The exclusion of oxygen during the reaction thus is highlycritical as well. After the aldehyde is formed, the protected hydroxylsare then liberated (e.g., deprotected) via base hydrolysis with anycompound or mixture of compounds having a pH level of at least 12, suchas NaOH, KOH, mixtures thereof, and the like. A mixture of the two basesis preferred.

[0044] Compositions comprising such compounds are also encompassedwithin this invention, particularly those of the compounds and bluingagents as liquids or as pellets. These broadly defined compounds as wellas the more specific types thus provide the necessary characteristicsfor clear applications (again, clear plastics, as one non-limitingexample) in terms of low color, low migration, liquid state, andeffective and thorough mixing within the target medium.

[0045] The proper amounts utilized in the various compositions andapplications are highly dependent on each of those separatepossibilities. Thus, in plastics, for example, the inventive UV absorberis added in an amount of from about 0.001 to about 1.5% by weight of thetotal plastic composition, preferably from about 0.01 to about 1.0%, andmost preferably from about 0.05 to about 0.5%. Such plastics may includeother standard additives, including antioxidants, clarifying agents,nucleators, acid scavengers, perfumes, colorants (for transparent, butcolored applications), antistatic agents, and the like.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] The general methods of making and utilizing the preferredinventive UV absorbers are as following:

[0047] Preparation of Compounds

EXAMPLE 1

[0048] Two thousand two hundred and eighty grams of vanillin, 20 g oflanthanum phosphate catalyst were charged to an autoclave. The autoclavewas then sealed, purged several times with nitrogen gas (to a pressureof 60 PSIG) and then pressurized to 5 PSIG of nitrogen. After heatingthe autoclave to 121° C., ethylene oxide was added to the reactionmixture until a total of 3960 g were added over time. Once all of theethylene oxide was added, the mixture was post-cooked for a total ofthirty minutes. The mixture was then cooled to 93° C. and stripped atreduced pressure for fifteen minutes in order to remove un-reactedethylene oxide. The product is a pale yellow liquid with a hydroxylnumber of 134.

[0049] Nine hundred and thirty eight grams of4-polyoxyalkylene-3-methoxy-benzaldehyde from the reaction describedabove, 30 g of Vitamin E, 8 g of glycine, 150 g of water and 305 g ofethyl cyanoacetate were charged to a 5 liter three neck round bottomflask. In the presence of a nitrogen atmosphere, the mixture was heatedto 70° C. and held for three hours. Upon cooling to room temperature,2500 ml of water was added and the mixture heated to 75° C. Afterphasing, the product layer was washed again with 2500 ml of water.Removal of water via a rotovap yielded 862 g of product that has alambda max of 358 nm in methanol. Its color value in methanol, which isdefined as absorption per gram of sample in 1000 ml of methanol, is 41abs/g/l.

[0050] One thousand grams of such UV absorber was then mixed with 5 g ofClearTint® PC Violet 480 (a bluing agent) from Milliken & Company. TheUV blend was then used for the application testing.

EXAMPLE 2

[0051] Four hundred and fifty-six grams of vanillin, one gram of KOHflake and four grams of proton sponge[1,8-bis(dimethylamino)naphthalene] were charged to an autoclave. Theautoclave was then sealed, purged several times with nitrogen gas (to apressure of 60 PSIG) and then pressurized to 5 PSIG of nitrogen. Afterheating the autoclave to 121° C., ethylene oxide was added to thereaction mixture until a total of 792 g were added over time. Once allof the ethylene oxide was added, the mixture was post-cooked for a totalof thirty minutes. The mixture was then cooled to 93° C. and stripped atreduced pressure for fifteen minutes in order to remove un-reactedethylene oxide. One thousand two hundred and fifty-three grams ofproduct (yield 97%) is obtained as a pale yellow liquid with a hydroxylnumber of 142.

[0052] 100.4 grams of 4-polyoxyalkylene-3-methoxy-benzaldehyde from thereaction described above, 0.82 g of Vitamin E, 0.92 g of glycine, 20 gof water and 26.3 g of ethyl cyanoacetate were charged to a 250-ml threeneck round bottom flask. In the presence of a nitrogen atmosphere, themixture was heated to 70° C. and held for three hours. Upon cooling toroom temperature, 150 ml of water was added and the mixture heated to75° C. After phasing, the product layer was washed again with 150 ml ofwater. After the removal of water via a rotovap, the residue liquid wasdiluted with 200 ml of MeOH. The mixture was then filtered through a5-micron filter to yield 80 g of light yellow liquid product that has alambda max of 360 nm in methanol. Its color value in methanol, which isdefined as absorption per gram of sample in 1000 ml of methanol, is 42abs/g/l.

[0053] One thousand grams of such UV absorber was then mixed with 5 g ofClearTint® PC Violet 480 from Milliken & Company. The UV blend was thenused for the application testing.

EXAMPLE 3

[0054] One thousand eight hundred and thirty grams of4-hydroxybenzaldehyde, 20 g of lanthanum phosphate catalyst (as usedabove in EXAMPLE 1) were charged to an autoclave. The autoclave was thensealed, purged several times with nitrogen gas (to a pressure of 60PSIG) and then pressurized to 5 PSIG of nitrogen. After heating theautoclave to 121° C., ethylene oxide was added to the reaction mixtureuntil a total of 3960 g were added over time. Once all of the ethyleneoxide was added, the mixture was post-cooked for a total of thirtyminutes. The mixture was then cooled to 93° C. and vacuum stripped forfifteen minutes in order to remove unreacted ethylene oxide. The productis a pale yellow liquid with a hydroxyl number of 144.

[0055] Eight hundred sixty grams of 4-polyoxyalkylene-benzaldehyde fromthe reaction described above, 30 g of Vitamin E, 8 g of glycine, 150 gof water and 305 g of ethyl cyanoacetate were charged to a 5 liter threeneck round bottom flask. In the presence of a nitrogen atmosphere, themixture was heated to 70° C. and held for three hours. Upon cooling toroom temperature, 2500 ml of water were added and the mixture heated to75° C. After phasing, the product layer was washed again with 2500 ml ofwater. Removal of water via roto vap yielded 862 g of product that has alambda max of 338 nm in methanol.

EXAMPLE 4

[0056] Eight hundred grams of resorcinol, 400 g of toluene and 4 g ofsodium hydroxide pellets were charged to an autoclave. The autoclave wasthen sealed, purged several times with nitrogen gas (to a pressure of 60PSIG) and then pressurized to 5 PSIG of nitrogen. After heating theautoclave to 121° C., ethylene oxide was added to the reaction mixtureuntil a total of 1920 g were added over time. Once all of the ethyleneoxide was added, the mixture was post-cooked for a total of thirtyminutes. The mixture was then stripped at 100° C. via rotovap in orderto remove unreacted ethylene oxide and toluene (water was addedperiodically to aid in the removal of toluene). The final product had ahydroxyl number of 304.

[0057] Two hundred sixty six grams of polyoxyalkylene resorcinol fromthe reaction described above, 193 g of acetic anhydride and 2 g ofN-methyl imidazole were charged to a three neck one liter round bottomflask. The mixture was heated under a nitrogen atmosphere to 130° C. andheld for three hours. After cooling to room temperature, the mixture wastransferred to a 2 liter one neck round bottom flask and 200 g of waterwere added. The mixture was stripped at 100° C. via roto vap in order toremove the acetic acid byproduct. After removal of the acetic acid, 310g of polyoxyalkylene resorcinol diacetate remained.

[0058] To a five liter three neck flask, 915 g of N,N-dimethyl formamidewas charged. While under a nitrogen purge, 34 g of 50% hypophosphorousacid was charged to the five liter flask. The resulting mixture wascooled to −5° C., at which 664 g of phosphorous oxychloride were addedslowly while maintaining a temperature between −5 and 0° C. Theresulting Vilsmeier complex was added to a mixture (purged withnitrogen) of 1138 g polyoxyalkylene resorcinol diacetate, 28 g of 50%hypophosphorous acid and 30 g of acetic anhydride. The temperature didnot exceed 25° C. during the addition of the Vilsmeier complex. Once theaddition was complete, the mixture was heated under a nitrogenatmosphere to 70° C. and held for two hours. Subsequently, the mixturewas cooled to room temperature and added to a solution containing 2492 gof water and 1566 g of 50% sodium hydroxide solution. This mixture washeated under a nitrogen atmosphere to 75° C. and phased. The productlayer was combined with 876 g of water, 546 g of 50% sodium hydroxidesolution and 92 g of 45% potassium hydroxide solution. While under anitrogen atmosphere, the mixture was heated to 70° C. and held for threehours. After cooling to room temperature, 1000 g of water were added themixture after it was neutralized with 93% sulfuric acid solution to a pHof 7. The resulting mixture was heated under a nitrogen atmosphere to75° C. and phased. The product layer was stripped and passed through afilter leaving 880 g of a pale yellow liquid. A 5% methanol solution ofthis liquid had a Gardner color (1953 series) of 6. An IR spectra ofthis product shows a peak at 1670 cm⁻ (aldehyde carbonyl stretch). Inmethanol, this substance has a lambda max of 273 nm in addition to asecond peak at 312 nm.

[0059] To a 500 ml three neck round bottom flask, 91 g of2,4-polyoxyalkylene benzaldehyde from the reaction described above, 3 gof Vitamin E, 0.85 g of glycine, 31 g of ethyl cyanoacetate and 20 g ofwater were charged. While under an atmosphere of nitrogen, the reactionmixture was heated to 70° C. and held for three hours. After cooling themixture to room temperature, 250 g of water were added and the mixtureheated under nitrogen to 75° C. The phased product layer was washedagain with 250 g of water. Upon stripping, 95 g of product remained. Inmethanol, this substance has a lambda max of 367 nm.

[0060] One thousand grams of such UV absorber was mixed with 8 g ofClearTint® PC Violet 480 from Milliken chemical. The UV blend was thenused for the application testing.

COMPARATIVE EXAMPLE 1

[0061] Two thousand two hundred and eighty grams of vanillin, 20 g ofsodium hydroxide catalyst were charged to an autoclave. The autoclavewas then sealed, purged several times with nitrogen gas (to a pressureof 60 PSIG) and then pressurized to 5 PSIG of nitrogen. After heatingthe autoclave to 121° C., ethylene oxide was added to the reactionmixture until a total of 3960 g were added over time. Once all of theethylene oxide was added, the mixture was post-cooked for a total ofthirty minutes. The mixture was then cooled to 93° C. and vacuumstripped for fifteen minutes in order to remove unreacted ethyleneoxide. The product is an amber liquid with a hydroxyl number of 134.

[0062] Nine hundred and thirty eight grams of4-polyoxyalkylene-3-methoxy-benzaldehyde from the reaction describedabove, 30 g of Vitamin E, 8 g of glycine, 150 g of water and 305 g ofethyl cyanoacetate were charged to a 5 liter three neck round bottomflask. In the presence of a nitrogen atmosphere, the mixture was heatedto 70° C. and held for three hours. Upon cooling to room temperature,2500 ml of water were added and the mixture heated to 75° C. Afterphasing, the product layer was washed again with 2500 ml of water.Removal of water via roto vap yielded 862 g of product, which has alambda max of 358 nm in methanol. Its color value in methanol, which isdefined as absorption per gram of sample in 1000 ml of methanol, is 25abs/g/l.

COMPARATIVE EXAMPLE 2

[0063] To a 500 ml three neck flask, 135 g of N,N-dimethyl formamide wascharged and purged with nitrogen. Once cooled to −5° C., 99 g ofphosphorous oxychloride were added slowly while maintaining atemperature between −5 and 0° C. The resulting Vilsmeier complex wasadded to a mixture (purged with nitrogen) of 169 g polyoxyalkylene (6EO)resorcinol diacetate and 4.5 g of acetic anhydride. The temperature didnot exceed 25° C. during the addition of the Vilsmeier complex. Once theaddition was complete, the mixture was heated under a nitrogenatmosphere to 70° C. and held for two hours. Afterwards, the mixture wascooled to room temperature and added to a solution containing 369 g ofwater and 232 g of 50% sodium hydroxide solution. This mixture washeated under a nitrogen atmosphere to 75° C. and phased. The productlayer was combined with 153 g of water, 95 g of 50% sodium hydroxidesolution and 16 g of 45% potassium hydroxide solution. While under anitrogen atmosphere, the mixture was heated to 70° C. and held for threehours. After cooling to room temperature, 112 g of water were added themixture after it was neutralized with 93% sulfuric acid solution to a pHof 7. The resulting mixture was heated under a nitrogen atmosphere to75° C. and phased. The product layer was stripped and passed through afilter leaving 110 g of a light orange liquid. A 5% aqueous solution ofthis liquid had a Gardner color (1953 series) of 7.

COMPARATIVE EXAMPLE 3

[0064] To a 500 ml three neck flask, 135 g of N,N-dimethyl formamide wascharged and purged with nitrogen. Once cooled to −5° C., 99 g ofphosphorous oxychloride were added slowly while maintaining atemperature between −5 and 0° C. The resulting Vilsmeier complex wasadded to a mixture (purged with nitrogen) of 169 g polyoxyalkylene (6EO)resorcinol diacetate and 4.5 g of acetic anhydride. The temperature didnot exceed 25° C. during the addition of the Vilsmeier complex. Once theaddition was complete, the mixture was heated under a nitrogenatmosphere to 90° C. and held for two hours. Afterwards, the mixture wascooled to room temperature and added to a solution containing 369 g ofwater and 232 g of 50% sodium hydroxide solution. This mixture washeated under a nitrogen atmosphere to 75° C. and phased. The productlayer was combined with 153 g of water, 95 g of 50% sodium hydroxidesolution and 16 g of 45% potassium hydroxide solution. While under anitrogen atmosphere, the mixture was heated to 95° C. and held for threehours. After cooling to room temperature, 112 g of water were added themixture after it was neutralized with 93% sulfuric acid solution to a pHof 7. The resulting mixture was heated under a nitrogen atmosphere to75° C. and phased. The product layer was stripped and passed through afilter leaving 107 g of a dark reddish brown liquid. A 5% methanolsolution of this liquid exhibited a Gardner color (1953 series) of 13.

[0065] To a 100 ml three neck round bottom flask, 37 g of2,4-polyoxyalkylene benzaldehyde from the reaction described above, 3 gof Vitamin E, 0.5 g of glycine, 10 g of ethyl cyanoacetate and 10 g ofwater were charged. While under an atmosphere of nitrogen, the reactionmixture was heated to 70° C. and held for three hours. After cooling themixture to room temperature, 100 ml of water were added and the mixtureheated under nitrogen to 75° C. The phased product layer was washedagain with 100 ml of water. Upon stripping, 30 g of product remained. Inmethanol, this substance has a lambda max of 367 nm.

COMPARATIVE EXAMPLE 4

[0066] To a 500 ml three neck flask, 136 g of N,N-dimethyl formamide wascharged. While under a nitrogen purge, 5.2 g of 50% hypophosphorous acidwas charged to the 500 ml flask. The resulting mixture was cooled to −5°C., at which 99 g of phosphorous oxychloride were added slowly whilemaintaining a temperature between −5 and 0° C. The resulting vilsmeiercomplex was added to a mixture (purged with nitrogen) of 170 gpolyoxyalkylene (6EO) resorcinol diacetate, 4.2 g of 50% hypophosphorousacid and 4.5 g of acetic anhydride. The temperature did not exceed 25°C. during the addition of the Vilsmeier complex. Once the addition wascomplete, the mixture was heated under a nitrogen atmosphere to 90° C.and held for two hours. Subsequently, the mixture was cooled to roomtemperature and added to a solution containing 369 g of water and 233 gof 50% sodium hydroxide solution. This mixture was heated under anitrogen atmosphere to 75° C. and phased. The product layer was combinedwith 153 g of water, 95 g of 50% sodium hydroxide solution and 16 g of45% potassium hydroxide solution. While under a nitrogen atmosphere, themixture was heated to 95° C. and held for three hours. After cooling toroom temperature, 112 g of water were added the mixture after it wasneutralized with 93% sulfuric acid solution to a pH of 7. The resultingmixture was heated under a nitrogen atmosphere to 75° C. and phased. Theproduct layer was stripped and passed through a filter leaving 100 g ofa dark reddish brown liquid. A 5% methanol solution of this liquid had aGardner color (1953 series) of 11.

COMPARATIVE EXAMPLE 5

[0067] One thousand grams of p-formyl-N,N-polyoxyethyleneaniline (7moles EO) were mixed with 124 parts of diethyl malonate and 30 parts ofammonium carbonate. The mixture was then heated between 70 and 75° C.for 10 hours. The reaction was monitored by the UV-Vis spectra of themixture. When the reaction was completed, as indicated by the presenceof an absorption maximum at 377 nm (A/gl=20.1), the product was thenfurther stripped under reduced pressure to yield the final product.

COMPARATIVE EXAMPLE 6

[0068] Seventeen g of 3,4-dimethoxybenzaldehyde, 70 ml of toluene, 1 gof piperidine and 15 g of ethylcyanoacetate were charged to a 250 mlthree neck flask. In the presence of a nitrogen atmosphere, the mixturewas heated to 110° C. and held for two hours. A precipitate formed oncooling. The precipitate was collected and recrystallized from 1:1toluene:acetone. After drying in an oven set at 70° C., a lightgreenish-yellow solid remained which has a lambda max of 357 nm inmethanol.

COMPARATIVE EXAMPLE 7

[0069] Seventeen g of 2,4-dimethoxybenzaldehyde, 70 ml of toluene, 1 gof piperidine and 15 g of ethylcyanoacetate were charged to a 250 mlthree neck flask. In the presence of a nitrogen atmosphere, the mixturewas heated to 110° C. and held for two hours. A precipitate formed oncooling. The precipitate was collected and recrystallized from 1:1toluene:acetone. After drying in an oven set at 70° C., yellow needlesremained. A methanol solution containing this substance has a lambda maxof 368 nm.

COMPARATIVE EXAMPLES 8 AND 9 Synthesis of Vanillin UVA ModelCompound—Ethyl 2-Cyano-3(4-Hydroxy-3-methoxyphenyl)propenoate

[0070]

EXAMPLE 8

[0071] Vanillin (15.2 g, 0.1 mol), ethyl cyanoacetate (12.5 g, 1.1 eq)and ethanol (100 ml) were mixed in a 250-ml 3 neck round bottom flaskequipped with a reflux condenser. While stirring, piperidine (1.5 g) wasadded and the whole mixture was refluxed for 2 hours. After cooling downto RT, the mixture was acidified to pH 5-6 by 10% HCl. The precipitateformed was collected by filtration, washed several times with methanoland dried in air to result a bright yellow crystalline product (9 g)which had a absorption of 360 nm in acetone.

EXAMPLE 9

[0072] Vanillin (15.2 g, 0.1 mol), ethyl cyanoacetate (12.5 g, 1.1 eq)and toluene (100 ml) were mixed in a 250-ml 3 neck round bottom flaskequipped with a reflux condenser. While stirring, piperidine (1.5 g) wasadded and the whole mixture was refluxed for 2 hours. After cooling downto RT, the mixture was acidified by a few drops of 10% HCl. Theprecipitate formed was collected by filtration, washed several timeswith methanol and dried in air to result a yellow crystalline product(19.2 g) which had a absorption of 360 nm in acetone.

[0073] Commercial samples of Tinuvin® 234 was obtained from Ciba. Sampleof Eastman Heatwave® UV concentrate was obtained and tested forcomparative purposes as well. Such commercial samples were thenintroduced within certain thermoplastic end-uses as for the otherComparative Examples noted above. The Eastman UV absorber was introducedby actually polymerizing the UV absorber with the thermoplastic itself.The Ciba UV absorber was added as a powder within a molten thermoplasticformulation and then mixed thoroughly therein.

[0074] Thermoplastic Composition Formation

[0075] The UV absorber was introduced within an injection moldingoperation for a polyester thermoplastic, for instance polyethyleneterephthalate. The liquid absorber was blended via agitation onto hot,dried polyethylene terephthalate resin (in pellet form) in a chamber,which minimized the adsorption of moisture, by the resin. The blend ofabsorber and pellets was gravity fed into the feed throat of themachine. In the feed section, melting was accomplished though theutilization of a heated (heat transferred from the barrel of themachine) screw extruder which rotated. The rotation of the screwprovided thorough mixing of the absorber and molten resin togetherproducing a uniform plastic melt which was injected into a mold in orderto form the intermediate thermoplastic article, for instance a parison.

[0076] The intermediate article (such as the parison) was allowed toequilibrate at normal room temperature and humidity before beingprocessed further. The article was positioned in front of a bank ofinfrared heaters that increased the temperature of the parison to itssoftening point. The heated parison was then transferred to a mold wherea rod was inserted into the parison stretching the end of the parison tothe bottom of the mold. Subsequently, pressurized air was blown into thestretched parison pushing the walls of the parison against the mold toform the desired thermoplastic article, such as a bottle, having anaverage thickness of about 15-20 mils.

[0077] Transmission Data for Polyester Resins

[0078] The percent transmission of UV light through 5 different PETbottle wall sections was measured on a Perkin-Elmer Lambda 35 UV-VisSpectrometer with a 50 mm Integrating Sphere. The wall thickness for allsamples is around 0.43 mm (17 mils). The UV transmission data issummarized in table 2. TABLE 1 PET Bottles for UV Transmission TestingBottle ID UV absorber loading and composition A (control) None B(Comparative) 1000 ppm Tinuvin ® 234 C (Comparative) Eastman Heatwave ®UV absorber (from Comparative Example 8) D 1000 ppm example 3 E 1000 ppmof example 1 F 1000 ppm of example 2 and 1000 ppm of Tinuvin ® 234 G1000 ppm of example 2 and 500 ppm of example 1

[0079] The transmittance spectra of the PET bottle wall sections weremeasured from 250 nm to 450 nm in 5 nm increments. The results are asfollows: TABLE 2 % Transmission of UV Light Through PET Resin WavelengthBottles Tested (nm) A B C D E 250 0.679 0.216 0.204 0.051 0.139 255 0.710.166 0.142 0.013 0.128 260 0.721 0.136 0.078 −0.025 0.078 265 0.7340.136 0.174 −0.017 0.050 270 0.816 0.132 0.162 −0.133 0.058 275 0.8350.122 −0.002 −0.116 −0.077 280 0.843 −0.045 −0.155 −0.035 0.028 2850.734 0.122 −0.123 −0.104 −0.074 290 0.702 0.089 0.053 −0.092 −0.080 2950.555 0.039 0.011 −0.175 −0.054 300 0.549 −0.017 0.006 −0.122 −0.089 3050.446 −0.004 −0.025 −0.070 −0.119 310 0.656 0.068 −0.079 −0.150 −0.114315 0.851 0.013 0.050 −0.058 0.026 320 6.071 0.436 0.206 0.718 0.780 32537.58 2.617 0.220 5.514 3.692 330 57.683 3.501 −0.330 7.907 4.931 33564.309 3.159 −0.070 7.553 4.983 340 67.429 2.602 −0.069 5.948 4.161 34570.121 2.265 0.074 4.180 3.130 350 72.762 2.236 0.070 2.785 2.300 35574.583 2.500 0.041 1.868 1.728 360 76.104 3.261 0.095 1.328 1.368 36578.368 4.853 0.093 1.040 1.267 370 80.465 7.642 0.426 0.930 1.207 37581.829 12.652 2.074 0.916 1.317 380 82.801 21.659 8.993 1.215 1.659 38583.594 35.960 26.268 1.902 2.530 390 83.953 53.233 48.346 3.286 4.718395 84.433 67.935 64.050 6.169 9.771 400 84.896 77.356 72.800 12.86320.208 405 85.308 82.362 77.255 25.844 36.351 410 85.654 84.707 79.61043.944 53.844 415 85.932 85.863 81.020 61.386 67.699 420 86.149 86.46682.089 73.656 76.392 425 86.501 86.954 82.985 80.690 81.153 430 86.66487.217 83.691 84.044 83.497 435 86.892 87.409 84.207 85.562 84.681 44087.016 87.570 84.756 86.323 85.345 445 87.196 87.768 85.045 86.68385.748 450 87.310 87.868 85.351 86.891 85.981

[0080] Since the lower % transmission represents better performance, itis evident that from a larger range of wavelengths, the inventive UVabsorbers provide greater overall protection for the target PET resin.The inventive UV absorbers provide much improved UV protection at longerwavelength range (between 370-390 nm). Furthermore, only the PET bottleswith the inventive UV absorbers can meet the specification oftransmission under 10% for wavelength below 390 nm.

[0081] Protecting the Content From UV Damage

[0082] The main objective to incorporate UV absorber into PET packagingis to protect the content from harmful UV damage. Such needs are moreacute in food packaging. It is generally known that UV light would causedegradation of various nutrients, such as vitamins. It is now found thatthe inventive UV absorbers offer much improved protection against UVdamage relative to the commercial UV absorbers.

[0083] The vitamin B group has a wide and varied range of functions inthe human body. Most B vitamins are involved in the process ofconverting blood sugar into energy. Diets rich in B vitamins areparticularly important for pregnant and breast-feeding women and forother people who require more energy, such as athletes and heavy-laborworkers. Vitamin B₂, Riboflavin, is very important in the production ofenergy. Vitamin B₂ can be found in milk, dried fortified cereals, andlow fat yogurt. Deficiencies affect the skin and mucous membranes.Though riboflavin is quite stable to heat, it is very sensitive tolight. It is particularly sensitive to ultraviolet light.

[0084] A study was conducted to determine the effectiveness of the PETpackaging to prevent the degradation of vitamin B₂ due to lightexposure. A stock solution of riboflavin was prepared by dissolving 50mg/L in deionized water. The stock solutions were protected from light.The PET bottles from previous experiment (listed in table 1) were used.The PET bottles were filled with the stock solution. The bottles wereplaced in a Q-Panel QUV Acelerated Weathering Tester with UVA-351 bulbs.The choice of UVA light bulbs is to simulate the exposure to fluorescentlight during warehouse, supermarket or other indoor storage. Thedegradation of the riboflavin was followed by monitoring the absorptionof the visible absorption peak at 444 nm. The control sample was coveredwith aluminum foil and was subjected to the same treatment. The testdata is summarized in table 3. TABLE 3 % Residual Riboflavin after LightExposure Light Exposure Duration (hours) Bottle ID 0 1 3 5 7 9 A (foiledcontrol) 100% 100% 100% 100% 100% 100% A (exposed) 100% 73% 25% 6% 3%<1% B 100% 92% 77% 59% 44% 31% D 100% 95% 86% 72% 62% 50% E 100% 96% 85%70% 60% 48% F 100% 100% 89% 81% 73% 62%

[0085] The data shows that the foiled control sample maintains the sameconcentration of riboflavin. Thus, the degradation is entirely caused bylight exposure. All PET bottles containing UV absorbers show much higherlevel of retained riboflavin than control. The bottles with theinventive UV absorbers show significant higher level of retainedriboflavin than the bottle with the best commercial product. Among allbottles, Bottle F shows the best protection of the content against lightexposure.

[0086] Colorimetric Data for Polyester Resins

[0087] Although other UV absorbers with longer wavelength absorptionhave been disclosed, they usually impart color within the polyesterarticle. For many of the packaging application, a colorless andtransparent package is essential. The inventive UV absorbers possess theexquisite balance of imparting exceptional UV screening ability and nocolor to the PET articles.

[0088] The Colorimetric data of the different PET bottle wall sectionswas measured on a Gretag-Macbeth ColorEye 7000A Spectrophotometer. TheColorimetric data, using the CieLab scale, specifically L*, indicatingthe lightness/darkness, and b*, indicating yellowness/blueness of thePET bottle wall section are as follows: TABLE 4 Colorimetric data of PETResins UV absorber (from Table 1, above, with ppm) L* b* Example 4 (1000ppm) 93.89 2.10 Example 1 (1000 ppm) 93.79 2.22 Comparative Example 1(1258 ppm) 95.51 6.25 Comparative Example 3 (873 ppm) 95.33 5.61

[0089] Thus, the comparative examples exhibit similar L* values(brightness) but with simultanouesly high yellowness (b* values).Measurements for these values are preferably at least 90 for L* and atmost about 2.5 for b* to signify a low yellowing resin with very lowamounts of graying bluing agents, and thus a very bright appearance.Attempts to reduce the b* value (e.g., yellowness) of the comparative UVabsorbers involved the addition of bluing agents which thus reduced thebrightness (L*) of the target resins to values below the target value of90.

[0090] Colorimetric Data for Liquid UV Absorbers

[0091] As stated before, being colorless is very important for thisapplication. The inventive process can reduce the level of color withinthe inventive UV absorbers. In this experiment, the UV absorbers weredissolved in methanol to make up a 5% solution. The Gardner color wasmeasured. Data is shown in the table 5. A higher Gardner color indicatesthat the UV absorber is more likely to impart color within the final PETarticle. TABLE 5 Gardner Color of UV Absorbers Sample (from Examplesabove) Gardner Color 1 10 4 11 Comparative Example 1 11 ComparativeExample 3 18

[0092] Thus, the data show that the inventive process significantlyreduce the level of color within the inventive liquid UV absorbers.

[0093] Extraction

[0094] Food packaging is one of the largest application that requires UVprotection within the packaging material. Therefore, exhibition ofnon-migration characteristics under normal use conditions is animportant requirement for the inventive colorless UV absorbers. Theirmigratory properties were studied by the following extraction test.

[0095] Polyester plaques containing the UV absorber additives wereprepared using standard compounding methods. Each plaque had a surfacearea of 12.5 in². The PET plaques were made using ClearTuf® 8006 PET(from M&G Polymers) resin while the PEN plaques were prepared using PENHypertuf® (from M&G Polymers).

[0096] For each additive, the following extraction procedure wasfollowed:

[0097] Solutions of 95% ethanol were used as food simulating solvent.USP 200 proof absolute ethanol was diluted with DI water to prepare theextraction solvents. Stainless steel pressure vessels havingTeflon®-lined tops were used as extraction vessels in this study. 125 gof extracting solvent and 6 plaques/vessel were employed in thesestudies. The plaques were arranged so that the plaques were immersed andexposed on all sides to the extraction solvent.

[0098] Six plaques were cut in half and placed in a stainless steelextraction vessel and 125 g of 95% ethanol (preheated to 70° C.) wasadded. The vessels were then sealed and placed in a 70° C. oven for 2hours, at which time they were then removed. Subsequently, the plaqueswere then removed from the extraction vessels and the solvent wasallowed to cool to ambient temperature. The extract solutions were thenanalyzed spectrophotometrically to determine if any UV absorbers hadbeen extracted from the target resins.

[0099] The extracts were analyzed spectrophotometrically to determinethe presence or absence of extracted colorant. A Beckman® DU 650spectrophotometer with a 10.00 cm path length cell was used. Theinstrument was first zeroed using the extract obtained from theuncolored polyester plaques. The extract from the extraction of theplaques containing the various additives was then scanned through theultraviolet/visible range to determine the presence or absence ofdetectable peaks at the additives' λ_(max) and the correspondingabsorbency. Higher absorption level at the additives' λ_(max) wouldindicate higher extraction level. The term “heated alcohol extractiontest” as it pertains to this invention encompasses such an analyticalprocedure as this in association with this invention.

[0100] The results are summarized in the following table 6 and 7. TABLE6 Extraction Results in PET Sample UV absorber (from Extraction ResultExamples above) Loading (absorption at λ_(max)) Comparative example 6284 ppm 0.62 Comparative example 7 272 ppm 0.60 Tinuvin ® 234 600 ppm0.20 Comparative Example 8 200 ppm 0.172 Comparative Example 9 200 ppm0.179 Example 1 600 ppm 0.02 Example 2 600 ppm Non-detectable

[0101] TABLE 7 Extraction Results in PEN Extraction Result Sample IDLoading (absorption at λ_(max)) Comparative example 6 284 ppm 0.016Comparative example 7 272 ppm 0.030 Tinuvin ® 234 600 ppm 0.003 Example1 600 ppm Non-detectable Example 2 600 ppm Non-detectable

[0102] Thus, the data shows that inventive UV absorbers show muchreduced extraction level that that of the comparative examples and thecommercial UV absorbers. The inventive UV absorbers are more suitablefor food contact applications. In the case of Comparative Examples 8 and9, such results as noted above in Table 6 indicate that introduction ofsuch UV absorbers (from the Pruett et al. patent) during the injectionmolding stage, rather than during the actual polymerization stage of thetarget thermoplastic results in highly undesirable extractionmeasurements, particularly in comparison with the polymeric UV absorbersof the instant invention.

[0103] While specific features of the invention have been described, itwill be understood, of course, that the invention is not limited to anyparticular configuration or practice since modification may well be madeand other embodiments of the principals of the invention will no doubtoccur to those skilled in the art to which the invention pertains.Therefore, it is contemplated by the appended claims to cover any suchmodifications that incorporate the features of the invention within thetrue meaning, spirit, and scope of such claims.

What is claimed is:
 1. A clear thermoplastic article having an averagethickness of at most 35 mils comprising at least one ultravioletabsorber compound exhibiting ultraviolet absorption characteristics overthe range of wavelengths from about 300 to about 400 nm such that saidarticle exhibits a UV transmission of at most 10% at the 390 nmwavelength; wherein said at least one compound exhibits an extractionlevel from said thermoplastic article measured as the level ofabsorbance exhibited by a heated alcohol extract solution after 2 hoursexposure of at most 0.1 absorbance units within a cell of 10.0 cmoptical length; and wherein said ultraviolet absorber comprises at leastone poly(oxyalkylene) chain of at least six moles of oxyalkylene.
 2. Theclear thermoplastic article of claim 1 wherein said ultraviolet absorbercompound exhibits an extraction level of at most 0.05 absorbance unitswhen subjected to a heated extraction test for 2 hours.
 3. The clearthermoplastic article of claim 2 wherein said ultraviolet absorbercompound exhibits an extraction level of at most 0.025 absorbance unitswhen subjected to a heated extraction test for 2 hours.
 4. The clearthermoplastic article of claim 3 wherein said ultraviolet absorbercompound exhibits an extraction level of 0.0 absorbance units whensubjected to a heated extraction test for 2 hours.
 5. A clearthermoplastic article having an average thickness of at most 35 milscomprising at least one ultraviolet absorber compound exhibitingultraviolet absorption characteristics over the range of wavelengthsfrom about 300 to about 400 nm such that said article exhibits a UVtransmission of at most 10% at the 390 nm wavelength; wherein said atleast one compound exhibits an extraction level from said thermoplasticarticle measured as the level of absorbance exhibited by a heatedalcohol extract solution after 2 hours exposure of t most 0.1 absorbanceunits within a cell of 10.0 cm optical length; and wherein saidultraviolet absorber is introduced within said thermoplastic at any timeduring the production of said article.
 6. The clear thermoplasticarticle of claim 5 wherein said ultraviolet absorber compound exhibitsan extraction level of at most 0.05 absorbance units when subjected to aheated extraction test for 2 hours.
 7. The clear thermoplastic articleof claim 6 wherein said ultraviolet absorber compound exhibits anextraction level of at most 0.025 absorbance units when subjected to aheated extraction test for 2 hours.
 8. The clear thermoplastic articleof claim 7 wherein said ultraviolet absorber compound exhibits anextraction level of 0.0 absorbance units when subjected to a heatedextraction test for 2 hours.
 9. The clear thermoplastic article of claim5 wherein said at least one ultraviolet absorber is introduced withinsaid thermoplastic article during the injection molding step for theproduction of said article.
 10. The clear thermoplastic article of claim9 wherein said ultraviolet absorber compound exhibits an extractionlevel of at most 0.05 absorbance units when subjected to a heatedextraction test for 2 hours.
 11. The clear thermoplastic article ofclaim 10 wherein said ultraviolet absorber compound exhibits anextraction level of at most 0.025 absorbance units when subjected to aheated extraction test for 2 hours.
 12. The clear thermoplastic articleof claim 11 wherein said ultraviolet absorber compound exhibits anextraction level of 0.0 absorbance units when subjected to a heatedextraction test for 2 hours.
 13. A clear thermoplastic article having anaverage thickness of at most 35 mils comprising at least one ultravioletabsorber compound exhibiting ultraviolet absorption characteristics overthe range of wavelengths from about 300 to about 400 nm such that saidarticle exhibits a UV transmission of at most 10% at the 390 nmwavelength; wherein said at least one compound exhibits an extractionlevel from said thermoplastic article measured as the level ofabsorbance exhibited by a heated alcohol extract solution after 2 hoursexposure of at most 0.1 absorbance units within a cell of 10.0 cmoptical length; and wherein said at least one ultraviolet absorber is aliquid prior to incorporation within said thermoplastic article and atroom temperature in its pure, undiluted state.
 14. The clearthermoplastic article of claim 13 wherein said ultraviolet absorbercompound exhibits an extraction level of at most 0.05 absorbance unitswhen subjected to a heated extraction test for 2 hours.
 15. The clearthermoplastic article of claim 14 wherein said ultraviolet absorbercompound exhibits an extraction level of at most 0.025 absorbance unitswhen subjected to a heated extraction test for 2 hours.
 16. The clearthermoplastic article of claim 15 wherein said ultraviolet absorbercompound exhibits an extraction level of 0.0 absorbance units whensubjected to a heated extraction test for 2 hours.
 17. The clearthermoplastic article of claim 1 wherein said article exhibits a b*value of at most 2.5 and a L* value of at least 90 on the CieLab scale.18. The clear thermoplastic article of claim 5 wherein said articleexhibits a b* value of at most 2.5 and a L* value of at least 90 on theCieLab scale.
 19. The clear thermoplastic article of claim 13 whereinsaid article exhibits a b* value of at most 2.5 and a L* value of atleast 90 on the CieLab scale.